class Main {
	static boolean isPrime(int x) {
		for (int i = 2; i <= x-1; i++) {
			if (x % i == 0)
				return false;
		}
		return true;
		
	}
	
	public static void main(String[] args) {
		for (int i = 3; i <= 97; i+=2) {
			if (isPrime(i) && isPrime(i+2)) {
				System.out.println(i + " and " + (i+2) + " are sister primes.");
				
			}
		}
	}
}
